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Modern Methods of Ferritic Nitrocarburizing (FNC) Open bed at temperature Loaded basket, ready for carousel Removal from fluidized quench 28 dia 48 depth.

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Presentation on theme: "Modern Methods of Ferritic Nitrocarburizing (FNC) Open bed at temperature Loaded basket, ready for carousel Removal from fluidized quench 28 dia 48 depth."— Presentation transcript:

1 Modern Methods of Ferritic Nitrocarburizing (FNC) Open bed at temperature Loaded basket, ready for carousel Removal from fluidized quench 28 dia 48 depth open basket H-13 section

2 Ferritic Nitrocarburizing (FNC) How we got here l 1900s – Dr. Adolph Fry Discovered that Nitrogen and Iron had affinity to one another. Discovered that Nitrogen and Iron had affinity to one another. Developed nitrogen iron equilibrium table Developed nitrogen iron equilibrium table Nitralloy steels Nitralloy steels Studied effect of adding other alloys Vanadium, Tungsten, Manganese, Molybdenum, Titanium Studied effect of adding other alloys Vanadium, Tungsten, Manganese, Molybdenum, Titanium

3 Ferritic Nitrocarburizing (FNC) Continued 2 l 1900s Adolph Machlet – New Jersey American Gas Company - Elizabeth American Gas Company - Elizabeth Applied for patents which were received June 24, 1913 Applied for patents which were received June 24, 1913 US saw no commercial benefit at the time US saw no commercial benefit at the time

4 l 1927 Pierre Aubert – Chicago At SME convention presented research for practical applications in Europe At SME convention presented research for practical applications in Europe Included railway steel, machine tools, auto, aviation. Included railway steel, machine tools, auto, aviation. Benefits – hard surface, core not changed, high wear, unaffected by temper, corrosion resistance. Benefits – hard surface, core not changed, high wear, unaffected by temper, corrosion resistance. Ferritic Nitrocarburizing (FNC) Continued 3

5 l 1928 – McQuaid and Ketchum Timken – Detroit Axle Co. Timken – Detroit Axle Co. Metallurgists – practical applications Metallurgists – practical applications Used work of Fry and Machlet as pivot point Used work of Fry and Machlet as pivot point l 1929 – Robert Sergeson Central Alloy Steel – Canton, OH Central Alloy Steel – Canton, OH Varying Al content in nitro alloy steel with effect of nickel Varying Al content in nitro alloy steel with effect of nickel Ferritic Nitrocarburizing (FNC) Continued 4

6 l V. O. Homberg & J.P. Walsted - MIT Effect of varying temperature – white layer Effect of varying temperature – white layer Equipment preheat and decarburization effect Equipment preheat and decarburization effect l Dr. Carl F. Floe – Assoc MIT Continued study of white (epsilon) layer Continued study of white (epsilon) layer The Flow Process – methods to change compound layer The Flow Process – methods to change compound layer l Eventually this research lead to Ion Nitriding – in effort to shorten cycle times, reduce distortion, and improve metallurgical properties. Ferritic Nitrocarburizing (FNC) Others

7 l Fluidized Bed Nitriding and FNC l Nitempering l Controlled Nitrocarburizing l Soft Nitriding l Triniding l Nitroc Process l Vacuum Nitrocarburizing l Nitrotec Process l Austenite Nitrocarburizing Types of Nitriding

8 l Process where N 2,C, and sometimes a very small degree of O 2 atoms are diffused into the surface of a ferrous substrate forming a compound layer and subsurface diffusion layer. l Done in relatively short period of time at sub critical steel temperatures l Wear properties, Corrosion (solder), and improved fatigue resistance. FNC – Thermochemical Diffusion

9 l Salt Bath Nitrocarburizing Started about 55 years ago commercially. Started about 55 years ago commercially – Germany patented Tuffride 1959 – Germany patented Tuffride 1970s – EPA regs prohibiting cyanide base materials 1970s – EPA regs prohibiting cyanide base materials Tufftride replaced with Melonite and French process called Sur-sulf Tufftride replaced with Melonite and French process called Sur-sulf These two processes still in use today. These two processes still in use today. Prominent Developments FNC

10 l Gas – Originally patented in 1961 by Joseph Lucas Industries Ltd. l 1965 – B. Presnosil Published results of study doing Gas. l During following quarter of a century – developed Triniding (NH 3 and exothermic gas), Nitemper, Lindure and a two stage process (Deganit) from Germany Prominent Developments FNC Continued

11 l An 1879 patent discusses baking minerals under fluidized bed conditions l Bed of finely-divided heated particles, usually Aluminum oxide made to behave like a liquid by moving exothermic and reactive gases through the medium Smooth or bubbly properties – determines fluidization quality. Smooth or bubbly properties – determines fluidization quality. Size and hetrogeneity (other offspring) of bubbles – influences rate of the solid mixing Size and hetrogeneity (other offspring) of bubbles – influences rate of the solid mixing Bed geometry, gas flow rate, type of gas distributor Bed geometry, gas flow rate, type of gas distributor Vessel features – baffles, screens, heat exchangers Vessel features – baffles, screens, heat exchangers Fluidized (FNC) Bed Phenomenon

12 l Plunging your hand into a fluidized bed (unheated of course) gives the sensation of placing your hand in a bucket of water. Light objects introduced in the bed will float if light enough. l Behaving as a liquid causes the entire introduced object (metal) to be in complete contact with the aluminum oxide separated by the reactive gas/gases that surround the media and cause diffusion and white layer creation. l The heat from the bed starts the diffusion Analogy of Fluidized Bed and Liquids

13 l Cleanliness of tool steel Mild to aggressive alkaline bath at elevated temperature – bed & part contamination Mild to aggressive alkaline bath at elevated temperature – bed & part contamination l Particle diameter – influences heat transfer In practice 100 micro mm (.3940 micro inches) In practice 100 micro mm (.3940 micro inches) l Bed material density Optimum value kg/cu m or lb/cu. ft. Optimum value kg/cu m or lb/cu. ft. l Fluidized velocity of gas/gases Fluidized (FNC) Heat Transfer Factors

14 l Optimizing gas/gases flow rate Between 2 to 3 times the minimum fluidization velocity Between 2 to 3 times the minimum fluidization velocity l Curve peaking To high – particle entrapment – high gas consumption To high – particle entrapment – high gas consumption To low - poor heat transfer – lack of uniformity To low - poor heat transfer – lack of uniformity Bed screws do not provide consistency Bed screws do not provide consistency Optimizing heat transfer to bed

15 Relationship of gas fluidization velocity to heat transfer rate Heat transfer rate falls off rapidly

16 Relationship of Bed Temperature to necessary Flow Rate Higher bed temperatures require less gas flow

17 Objective to get maximum heat transfer to part and optimize velocity of the gas/gases Heat transfer rate falls off rapidly without optimized gas flow rate Higher bed temperatures require less gas flow

18 l Computer control and automation l Adjustable ceramic screens l Eclipse valves with flow meters l Sensor feedback to computer controls and automation system Now a better way to attain repeatability - flow and heat First Fully Automated System in the United States and Canada

19 H-13 after only 2 hours in bed (N 2,NH 3,CH 4 ) Compound layer 5-20 microns = inches Diffusion layer microns = inches Vickers hardness from surface

20 l Development of Hard PVD (below 700 o F) thermochemical surface treatments in Australia – grant by IR & D board l Coatings such as vanadium carbonitride, and chromium carbonitride at low temperature by diffusion-based treatments l Patents already applied for and equipment available to perform new range of low temperature surface treatments – Qab. Future Uses of Fluidized Beds

21 Range of coatings - QAB Nitrogen and Alloy based below 700 o C Carbon based above 700 o C Courtesy of QHT Ray Reynoldson Nitrogen Based Nitriding Ferritic Austenitic Alloy Based Chromium Vanadium Titanium Niobium Carbon Based Carburizing CD Carburizing Carbonitriding

22 Process to form CrCN - QAB Aluminum Oxide media to obtain CrCN is coated Courtesy of QHT Ray Reynoldson

23 Hardness Profile - QAB Qab Profile for CrCN and Nitrocarburized structure Courtesy of QHT Ray Reynoldson Thickness controlled by time of processing CrCN = 1550v NitroC = 950v

24 Distribution of Elements in White Layer % of Cr highest near surface Thickness controlled by time of processing CrCN = 1550v NitroC = 950v Courtesy of QHT Ray Reynoldson

25 Field test results CrCN Courtesy of QHT Ray Reynoldson

26 TOOLING CIRCLE OF LIFE TOOLING CYCLE OF LIFE Badger Metal Tech, Inc. Badger Metal Tech, Inc Toll Free Want more information regarding our capabilities regarding fluidized bed treatments? Visit our website and click on the flame logo at the top of our home page


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